The present invention relates to an improved security seal and lock and, more particularly, to an improved security seal and lock of the type which includes a robust housing, usually, but not necessarily, made of metal, and a flexible metal cable, one end of which is permanently held in the housing and the other end of which is selectively insertable into and through the housing in a first direction but is not removable in a reverse direction from the housing once so inserted.
Housing-and-cable devices for sealing and locking lockable element such as hasp on a door are known. See for example British Patent 1880 (Issue Jan. 23, 1913) and the following U.S. Pat. Nos. 3,994,521 to Van Gompel; 4,049,303 to Irwin, et al.; 3,770,307 to Van Gompel; 4,747,631 to Loynes, et al.; 5,092,641 to Penick; and 4,216,568 to Anderson, which patent is not, strictly speaking, a patent relating to a security seal and lock but which describes a metal-wire-tensioning apparatus which is constructed and which operates similarly to the seals/locks of the foregoing patents.
Typically, housing-and-cable seals and locks may be used to immobilize the door hasp of shipping vehicles such as railroad boxcars and semi-trailers. Such use provides a method of rendering difficult unauthorized access to goods and materials contained within the boxcars in the semi-trailers. In the event that unauthorized entry does occur as a result of breaking or disintegrating the seal and lock, a visual indication of such unauthorized entry is provided.
It has been, and continues to be, a goal of suppliers of security seals and locks of the housing-and-cable type to provide a seal and lock which is simple in construction, which can be emplaced on the vehicle or container to be safeguarded without the use of special tools, and which cannot be removed unless substantial effort is expended to destroy the device.
In typical prior art security seals and locks of the housing-and-seal type under discussion, one end of a metal cable is more or less permanently affixed to, or more preferably, mounted within, a metal housing. The housing includes a path or passage therethrough along which the other end of the cable may be inserted into, through and out of the housing. The passage or path intersects a cavity within the housing. The cavity may be, in part, defined by a wall or surface which slopes away from the point of entry of the cable into the housing. The cavity may also be slightly skewed relative to the passage way so that a wall thereof slopes away from the point of entry of the cable into the housing.
A ball or disk is located within the cavity. The ball or disk simultaneously engages both the sloping cavity wall and the cable after its insertion. Typically a biasing member such as a spring urges the ball or disk toward the point of entry of the cable into the housing.
Entry of the cable into and through the housing and along the path causes the cable to engage the ball or disk and to move the ball or disk against the action of the biasing member away from the point of entry of the cable into the housing. In actual use, the insertion of the cable into the housing occurs after the cable has been passed through appropriate holes or openings in a hasp or other lockable element of a door or closure on a boxcar, trailer or other vehicle or container so that the now looped cable immobilizes the hasp or other lockable member.
An attempt to withdraw the cable from the housing by moving it in a reverse direction causes the cable to frictionally engage the ball or disk moving it in the direction of the point entry of the cable. At the same time, the biasing member also acts to move the ball or disk in this same direction. Ultimately, after a small amount of movement of the ball or disk toward the point of entry of the cable, the ball or disk becomes jammed between the cable and the narrowing space defined by the sloped wall of the cavity. Ultimately, this jamming effect becomes so great as to render quite difficult, if not prevent, removal of the cable from the housing without breaking the housing or cutting the cable.
Where a ball is used, it has been found that there is some possibility of withdrawing the cable from the housing if a pulling force and a twisting force are simultaneously applied to the cable. This is apparently due to the fact that twisting causes the ball to roll; such rolling to some extent ameliorates or avoids the jamming of the ball into the cable so that sufficient force to prevent the cable's withdrawal is not applied.
Accordingly, one object of the present invention is the provision of a housing-and-cable lock and seal which is simple in construction, which can be emplaced without the use of special tools which cannot be removed without destruction of the device and which obviates defeat by simultaneous twisting and pulling of the cable.